Wednesday, January 9, 2013

Apple Box 3 - composting with black soldier fly

Last swap, Joe talked about the benefits of using black soldier fly larvae to compost kitchen scraps, much in the same way that a worm farm operates.

Black soldierfly have a rather short and desperate adult life, with the sole purpose of finding a mate, a pile of rotting compost, and a good pick up line before dropping dead.

BSF larvae eat just about any kitchen scraps including meat and dairy, as well as the usual fruit and vegetable leftovers, and can be cultivated in much the same way as composting worms, to break down food waste. A BSF composting unit can be easily built from materials found at your local hardware, and once a colony has been established they can consume food waste much faster than worms. The larve themselves make a fantastic feed for chickens and even fish. BSF larvae are high in both protein and calcium, which is perfect for chooks. they are non invasive and do not enter houses or spread disease like other flies.

Our black soldierfly composter

Our Black Soldier fly composter

Here is how it works. Food scraps go inside and the female BSF are attracted by the scraps. They fly in through the pipe at the top and down into the bin where they lay their eggs (in the hundreds). They like to lay their eggs in crevasses, so some sheets of corrugated cardboard attached to the inside make great maternity wards. the eggs hatch and the larvae fall on the food scraps, and get to work munching it up.

to begin a colony, start with a small amount of vegetable scraps. As they begin to break down, the adult fly's will naturally be attracted and enter the composter to lay their eggs. this can take some weeks, so be patient. BSF are most active during spring and summer, which after the best times to begin a colony.

the larvae crawl up the pipes and into Jo's Tupperware container... thanks darling...sorry

 As the larvae mature they develop the instinct to climb to higher ground. The larvae find their way to the pipes and climb up them, then slide down into the separate storage container, where they are unwittingly trapped to be fed to the chooks.

Keep the composter in the shade, out of direct sunlight.

the larvae hard at work on one of our defiant choko's and watermelon rind

Make your own
there are a number of DIY designs on the net. we made ours using a clip lock tub, some PVC pipe parts, , some hessian and fly screen, a saw and a drill. The key is to angle the pipes at 35 degrees so that it is not too steep for them to climb.include some ventilation holes and cover with fly screen, and some drainage holes in the bottom, which you can cover with hessian. It takes less than half a leisurely hour to put together and cost us about $40 or you could buy one of the fancy ones online for about $200.

the main benefits are:
1. a very efficient method of waste disposal
2. meat and dairy waste can be added to established colonies, unlike regular composting methods, reducing your waste output.
3. the larvae make an excellent source of food for poultry and fish, and can be frozen for later use.
4. they don't spread disease like other flies, and rarely enter the home.
5. they emit a natural repellent to other flies once the colony has been established.

The smell can be an issue if you add more waste than they can consume. Sawdust or coffee can help here too.